Fitting new gear is one of the more satisfying jobs on any model, and it’s genuinely straightforward if you take it in order.
1. Remove the old gear completely, including any old thread-lock residue on the bolts, and inspect the fuselage mounting points for damage before fitting anything new — there’s no point bolting fresh gear to a cracked or soft mounting rail.
2. Dry-fit before you commit. Offer the new gear up to the mounting points without any fasteners tightened, and check the leg sits square to the fuselage centreline and that the wheel axles will clear any cowl, wheel pant, or fuselage side when the wheels are fitted.
3. Use the correct grade of fastener, torqued to a sensible value by feel rather than gorilla-tightened — carbon fibre mounting plates can crack under excessive clamping force just as easily as they can crack from flight loads. If in doubt, a drop of thread-lock on a moderately tight bolt beats an over-tightened one.
4. Check axle alignment with the gear bolted down — sight along both wheels from directly behind the model to make sure they’re parallel to each other and to the fuselage. Toe-in or toe-out, even slight, will cause the model to pull on take-off roll.
5. Fit wheels and pants last, and spin each wheel by hand to check for free rotation with no rubbing against pants or fuselage before your first flight.
6. Do a firm hand-push test on each gear leg, simulating a moderate landing load, before you ever trust it to a real one. If anything flexes further than you’d expect or you hear any cracking sound, stop and re-check the fit.
Take your time on step 3 in particular — most gear failures we hear about trace back to fasteners rather than the gear itself.
Take a look at our Carbon Fibre undercarriage for 50e and 50 size nitro Narrow Fit YAK50e 50e for a solid example of correctly sized gear.